Northstar Engines and System Technical Discussion Discussion, Is the N* overrated? in Cadillac Engine Technical Discussion; Factory rating is 300hp, but this being said:
Originally Posted by eldorado1
Our trannies use up about 23&amp;#37; of the ...

Is the N* overrated?

Factory rating is 300hp, but this being said:

Originally Posted by eldorado1

Our trannies use up about 23&#37; of the power the motor is putting out.

So 300hp net with a 23% drivetrain loss is 231whp, correct? How many here have dyno'd 231whp on a dyno without any modifications of any sort? I have done some research and see that number is being achieved with mods like induction and exhaust, but not factory stock.
The original N* was rated 275hp so ~211whp, which seems more realistic assuming about 20whp is being gained from induction and exhaust mods = 231whp (which should have been the factory number).

So question is was the 25hp added to the newer N* real, or was it just for print? I would like to see dyno sheets for all N* if you have any, both 275hp version and 300hp version. Or if anyone has more details to this I have overlooked, I am open ears (or eyes in this case) Thanks for any input or opinions.

Re: Is the N* overrated?

Originally Posted by airfuel2001

Factory rating is 300hp, but this being said:

So 300hp net with a 23% drivetrain loss is 231whp, correct? How many here have dyno'd 231whp on a dyno without any modifications of any sort? I have done some research and see that number is being achieved with mods like induction and exhaust, but not factory stock.
The original N* was rated 275hp so ~211whp, which seems more realistic assuming about 20whp is being gained from induction and exhaust mods = 231whp (which should have been the factory number).

So question is was the 25hp added to the newer N* real, or was it just for print? I would like to see dyno sheets for all N* if you have any, both 275hp version and 300hp version. Or if anyone has more details to this I have overlooked, I am open ears (or eyes in this case) Thanks for any input or opinions.

Re: Is the N* overrated?

Originally Posted by AJxtcman

Not all PCM programs are created equal

I agree, but GM created them all to equal 300hp and it seems they don't stack up?

In 1999 the Ford Mustang Cobra was rated 320hp and people complained that their dynos didn't show that power, and Ford was required (or heavily persuaded) to recall all the 32v Cobras that year and install better exhaust, so why didn't Cadillac do the same if what is said is in fact true? (Sorry 50&#37; of my posts have reference to a Mustang)

Re: Is the N* overrated?

Originally Posted by airfuel2001

I agree, but GM created them all to equal 300hp and it seems they don't stack up?

I know better than that.
Trust me
I have about 50 on paper and they are all different. I am mostly looking at z or w rated tires. I have some odd country programs, but I have about 50 different ones. Most of them are just for 2000 to 03. If I started pulling up S and H rated tires I would be over whelmed.
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I put together a DHS that ran against a VIN 9 car. It is Bert's Kill so you will have to wait, but that 275 horse is no 275 anymore. Nothing internal in the engine.

Re: Is the N* overrated?

Originally Posted by AJxtcman

I know better than that.
Trust me
I have about 50 on paper and they are all different. I am mostly looking at z or w rated tires. I have some odd country programs, but I have about 50 different ones. Most of them are just for 2000 to 03. If I started pulling up S and H rated tires I would be over whelmed.
.
I put together a DHS that ran against a VIN 9 car. It is Bert's Kill so you will have to wait, but that 275 horse is no 275 anymore. Nothing internal in the engine.

You are going to a different page, I know there are different spec cars. Issue is they were ALL rated 300hp, so they ALL should have made at least 300hp. We all are in agreeance that one of the biggest hinderances on these cars as far as making power is the factory PCM tune. But GM says their shitty tune (no matter the speed spec) is good for 300hp (231whp) and it is not.

Re: Is the N* overrated?

Originally Posted by airfuel2001

You are going to a different page, I know there are different spec cars. Issue is they were ALL rated 300hp, so they ALL should have made at least 300hp. We all are in agreance that one of the biggest hinderances on these cars as far as making power is the factory PCM tune. But GM says their shitty tune (no matter the speed spec) is good for 300hp (231whp) and it is not.

No
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That is my point.
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A engine that was on the dyno was rated at 300. It was not certified.

Re: Is the N* overrated?

I think that what AJ is saying (regarding the SAE ratings) is that both ratings are correct. The older L37 Northstars are rated at 300 hp. The newer L37 Northstars are rated at 292 hp, UNDER THE SAE J1349 spec. It's like gross vs. net ratings. Or old EPA MPG ratings vs. new EPA MPG ratings. Both old and new are "correct" in that the results are accurate to the method. The methodology was updated to try to better replicate real world conditions (in both examples, hp rating and EPA MPG rating).

The rating of a VIN 9 1996 Northstar engine is 300 hp. Will you see that at the wheels? Who knows -- it depends on the condition of your transmission and fluid, the weight of your wheel/tire package, etc. But there are too many unknown variables in a chassis dyno to know FOR SURE what your engine makes. We can guesstimate that the transmission consumes 23&#37; of the hp. What if it's only 20%? What if it's 25%? At 20%, 300 = 240 hp on a chassis dyno. But at 25%, 300 = 225 on a chassis dyno.

The only true measurement would be to dyno it at the crank, just as Cadillac did, and find out. Otherwise, you're just spinning your wheels, so to speak, trying to ascertain how much hp your transmission consumes to figure out how much hp an engine might make. Keep in mind also that an engine with 80,000 miles won't likely make the same power numbers as a new one.

In other words, I would totally believe a street-driven car with 50,000 miles putting down a number of 215 hp on a chassis dyno, even if the engine is supposed to put out 300 hp. Maybe the transmission is eating up 27% of the power (81 hp). 215 hp + 81 hp loss = 296 hp. If the difference between the rating and the actual output is only 4 hp, as in this case, I'd be impressed.

Re: Is the N* overrated?

Another question you have to ask is what were the conditions of the test for the 300hp and 275hp ratings? Is this installed in a simulated vehicle? With factory induction and exhaust? Are all the accessories installed? (water pump, alternator, power steering, AC compressor)

I don't know the answer to that... I know they recently changed those conditions, and the 4.4L SC N* was rated at 469hp then changed to 440hp. Same engine. 29hp "disappeared". Or maybe it was vice versa.